Studies on the transesterification of polycarbonate/poly(ethylene terephthalate) blends. I: Mechanisms and extent of reaction

Transesterification of polycarbonate/poly(ethylene-terephthalate) (PC/PET) blends and the reaction extent were investigated by DSC, FTIR, 1H NMR and Soxhlet extraction. A new characteristic peak appeared in the FTIR spectrum of PC/PET blends after heat treatment, which indicates that new copolymers were formed in the transesterification of the PC/PET blends. The reaction extent was characterized by the absorbance ratios of the FTIR characteristic bands. The reaction extent was associated not only with the reaction conditions but also with the composition of the blends. These results were confirmed by chemical analysis of the extracted products in CH2Cl2 solvent and FTIR analysis. For all the blends studied, the blend with 50/50 wt% had the highest reaction extent. The reaction mechanisms and extent were also confirmed by 1H NMR analysis.